Electroradiant siren



March 18 1924, 1,486,887

.1. H. HAMMOND, JR

ELECTRORADIANT SIREN Original Filed July-13 1914 4 ,Wl gmwmza y w?Z/Wwqsf Patent arl 18, 1924.

ELECTRORADIANT SIREN.

`Application led. Julyl 13, 1914, Serial No. 850,621. Renewed July 24,1923.

To all whom t may concern.'

Be it known that I, J oHN HAYs HAMMOND, Jr., a citizen of the UnitedStates, and a resident of Gloucester, in the county of Essex and Stateof Massachusetts, have invented an Improvement in Electroradiant Sirens,otwhich the followingdescription, in connection with the accompanyingdrawings, is a specification, like characters on the drawingsrepresenting like parts.

Some of the objects of this invention are to provide means for emittingelectro-radiant energy in the form of siren waves; to provide means forautomatically emitting electroradiant energy in the form of siren waves;to provide means for automatically emitting electro-radiant energy inthe form of siren waves in combination with means-to modify the actionof the transmission means to cause the same to emit waves of a constantfrequency; and to provide other improvements as will appear hereinafter.

The accompanying drawing shows diagrammatically one form of wave sirenconstructed in accordance with this invention.

Referring to the drawing, one embodiment of this invention comprises analternator, or other suitable source of energy 1 in circuit: with theprimary 2 of a transformer, of which the secondary is indicated at 3 asin a closed oscillatory circuit 4, having a suitable condenser 5, sparkgap 6 and rimary 7 of a transformer, the secon ary whereor` is indicatedat 8 as forming part of the aerial or antenna 9. The oscillatory circuit4 is in series by means of a conductor 10 with an inductance 11, inco-acting relation with which lis a switch 12 preferably-continuouslyrotated by any suitable means (not shown), so as to vary the amount ofinductance thereby thrown into the oscillatory circuit 4. Leading fromthe switch 12 is a conductor 13 having a switch 14 adapted to makesuitable contact with a terminal 15. Mounted in suitable relation to theswitch 14 is an electromagnet 16, and connected to one end of the collof this magnet 16 is a conductor 17 leading to ground at 18. So long asthe switch 14 is open, the inductance 11 or aportion thereof is inseries with the inductance 7 of the oscillatory circuit 4; that is, acircuit exists through the inductance 7, the inductance 11, the switch12, the condenser 5 and the spark gap 6. When, however, the magnet 16 isenergized, the switch 14 is closed, and the entire inductance -11 isshort circuited and will therefore have no edect upon and will not beincluded in the described circuit.

The aerial or antenna 9 is provided with a conductor 19 having asuitable inductance 20 in operative relation to which is a switch 21adapted to be preferably continuously rotated by any suitable means (notshown).

Leading from the rotary switch 21 is a conductor 22 having a terminal 23and also leading to the ground 24. Pivoted to swing into and out ofengagement with the terminal 23 is a switch 25 which is normally heldopen or out of engagement with the terminal 23 by means of a spiralspring 26. This switch 25 is connected to the conductor 19 by a branchconductor 27 and is arranged to form an armature for and to becontrolled by a fixed electro-magnet 28. One end of the coil of theelectro-magnet 28 is grounded as at 18 through a conductor 29, the coilof the electro-magnet 16, andthe conductor 17. The other end of the coilof the electro-mag net 28 is grounded as at 30 through a conductor 31containing a battery 32 and arranged to be controlled by a manuallyoperated switch 33.

As long as the switch 33 remains open, the switch 25 will remain openand the aerial or antenna 9 will be grounded as at 24 through theinductance 8, the conductor 19, a variable part of the coil 20, therotary switch 21 and the conductor 22. When, however, the switch 33 isclosed, thus energizing the magnet 28 and closing the switch 25, theentire inductance 20 will be short-circuited, and the aerial 9 will begrounded as at 24 through the inductance 8, the conductor 19, the branchconductor 27, the switch 25, the terminal 23, and the conductor 22.Also, when the switch 33 is open, the electro-magnet 16 will bedeenergized and consequently the switch 14 will remain open and theprimary coil 7 will be in series with the conductor 10, a variableortion of the coil 11, the rotary switch 12, tlie conductor 13 and thesecondary coil 3, but when the switch 33 is closed, the electro-magnet16 will be energized thus causing the switch 14 to engage against thecontact 15 and thus short-circuit the entire coil 11 and connect theprimary coil 7 directly in series with the secondary coil 3.

ln the operation of this improved system, the switch 33 is normally leftopen and the switches 12 and 21 are normally rotated in unison therebysimultaneously causing a constant variation in the elective lengths ofthe two coils 11 and 20 which are in series respectively with theprimary and secondary coils 7 and 8. The two coils 11 and 20 and the tworotary switches 12 and 21 are so arranged and proportioned that Whilethe switch 33 is open and the two rotary switches 12 and 21 are inoperation, the closed oscillatory circuit includin the primary coil 7and a varible portion o the coil 11 will always be maintained inresonance with the open aerial circuit including the secondary coil 8and the variable portion of the coil and the open aerial circuit 9 willbe caused to emit electroradiant waves which will be constantly vvariedin frequency and consequently in Wave I length between predeterminedlimits, the

variations in frequency occurring in periodic cycles in each of whichthe frequency is varied ste by step through a large number of smal stepsfrom a predetermined given frequenc to a predetermined second frequency.en the coils 11 and 20 are short-circuited by closing the switch 33, ashereinbefore described, the open aerial circuit 9 Will be caused to emitelectro-radiant waves having a predetermined frequency and acorresponding wave len th, for instance having a frequency whigh willgive a wave length of approximately 3000 meters.

Although only a single form has been shown herein in which thisinvention may be embodied it isto be understood that the invention isnot limited to any specific construction but might be applied in variousforms without departing from the spirit of the invention or the scope ofthe appended claims.

Claims:

l. The combination with means for transmitting radiant energy in theform of siren waves, comprising an open aerial circuit, a closedoscillatory circuit, a pair of elements arranged to be movedcontinuously to simultaneously vary the electrical values of saidcircuits respectively to maintain said circuits in resonance, and meansfor simultaneously short circuiting said elements to render saidelements ineiective while moving to vary the electrical values of saidcircuits.

2. The combination with means for transmitting radiant energy in theform of siren Waves, com rising an open aerial circuit, a closed oscilatory circuit, a pair of elements arranged to be rotated continuously tosimultaneously vary the electrical values of' said circuits respectivelyto maintain said circuits in resonance, and means for simultaneouslyshort circuiting said elements to render said elements ineiective whilemoving to vary the electrical values of said circuits.

In testimony whereof, name to this speciication, two subscribingwitnesses.

JOHN HAYS HAMMOND, JR. Witnesses:

F. J. Bm, JN0. P. Konsum.

I have signed my in the presence of

